The collector comes very close to the bellhousing and that's where the problem lies. I always thought the problem would be contact with the shock towers but I think they could go up 1/2-3/4" with lots of room. Note, where the tubes snake around beneath, around the steering box, that's another question. I'm hoping someone comes in to this question and says they run High Port heads with a 3/4" raised port and ground down the bellhousing and it all fits. That's what I hope happens